Telephone system



E. s. PETERSON TELEPHONE SYSTEM Filed Jan. 5, 1931 14 SheetS-Shet 1 Jam-film 551111511 5] 5.1 5 E'FSUTL m3 i l: NE m3 E Si may E in o mmw 0 Nmi June 26, 1933.

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TELEPHONE SYSTEM Filed Jan. 5, 1931 14 Sheets-Sheet 4 E June 20, 1933a REGISTER-SENDER E. S. PETERSON TELEPHONE SYSTEM Filed Jan. 5, 1931 14 sheets-sneer 6 v M21643 M 645 -11 it {Q ITEfiEE Edward fil ezersmn June 20, 1933.

REGISTER SENDER E. s. PETERSON 1,914,383

TELEPHONE SYSTEM Filed Jan. 5, 1931 14 Sheets-Sheet 7 dLL/ard June 20, 1933. s. PETERSON I TELEPHONE SYSTEM 14- Sheet-Shaet 8 Filed Jan. 5, 1931 June 20, 1933., E, s. PETERSON TELEPHONE SYSTEM Filed Jan. 1931 14 Sheets-Sheet 9 Jame 20, 1933. E s PETERSON 1914 33 TELEPHONE SYSTEM Filed Jan. 5, 193.1 14. Sheets-Sheet l0 14 Sheets-Sheet 11 Ed 5 F E, s. FETERSGN TELEPHONE SYSTEM Filed Jan. 5, 1951 June Z@, 1933.

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TELEPHONE SYSTEM Filed Jan. 5, 1931 14 Sheets-Sheet '13 J Q 3; Q g 6N Q 2 g g E h. H. m

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Patented June 20, 1933 UNITED STATES PATENT OFFICE EDWARD S. PETERSON, OI CHICAGO, ILLINOIS, ASSIGNOR, BY IESCNE ASSIGNMENTS, TO

ASSOCIATE!) ELECTRIC LABORATORIES, INC., OF CHICAGO, ILLINOIS, A CORPORA- TION OF IDELAIWAIR'E TELEPHONE SYSTEI Application filed January 5, 1981. Serial No. 606,657.

The present invention relates to telephone systems in general, but is concerned more particularly with telephone systems whereln automatic switches are operated under the control of an operator to set u the connections desired by callin subscri ers.

The system disclose herein may be considered an improvement over the systems disclosed'in the following patents and applications:

Patent 1,752,543, granted April 1, 1930 to Ruggles.

Patent 1,760,640, granted May 27, 1930 to Gohorel.

Patent 1,776,570, granted Sept. 23, 1930 to Ruggles.

, Application S. N. 237,140, filed Dec. 2, 1927 by Ruggles.

Application S. N'. 270,198, filed Apr. 16, 1928 by Saunders et al.

Application S. N. 297,631, filed Aug. 6, 1928 by Peterson et al.

General description rangements whereby a part of the lines entering an exchange may be local-battery, semi-automatic lines from which outgoing connections are set up through automatic switches under the control of an operator, .while the remaining lines may be regular common-battery automatic lines from which the automatic switches are directly cin- I'- rangements are provided for giving standard reverse-current supervision when calls are made to local-battery lines, as well as when calls are made to common-battery automatic lines, thus providing for the correct operation in case calls are from operators switchboards (private branch operators switchboards, for example) and providing also for the operation of meters, or message registers, in case it is desired to give metered service.

Amongst the various specific features of the present invention, the following are listed as being more or less outstanding.

1. In order to relieve those subscribers to pay a higher rental of be in series with the additional battery of dry cells for impressing a potential across the conductors of the line as long as the. receiver is removed; The resulting currentfiow takes the place of the ringing current generated by the hand generator, as will be i hereinafter described.

2. In order to maintain the line relay of a calling line switch 0 rated and to thereby maintain the operating chain circuit open so as to avoid the so-called double plunging of line switches, a locking circuit for an operated line relay is maintained closed until the master-switch operation has been started 'as a result of the seizure of the trunkline by the operated line switch, whereupon the locking circuit is opened to release the line relay of the operated line switch.

This feature may be applied to plunger line switches generally, as it obviates the use of a copper collar or copper slug on the armature end of the line relay.

3. In order that a calling subscriber shall know whether or not the operation of his ,hand generator to signal the operator has been effective in starting the apparatus in the central exchange to bring the operators attention to the call, arrangements are made for sending back a special tone to the calling line from the time the lineswitch operates until the calling subscriber is placed in communication with the operator. This is of special value on account of thefact that a party-line subscriber may finish a conversation and forget to operate his hand'generator to cause the connection to be released. In this case the application of ringing current made by the next subscriber on the party line, may result merely in the release of the previous connection and not in the signalling of the operator. With the improved arrangement just mentioned, a subscriber does not hear the o rator tone on the line in such a case and e is expected to ring again so as to cause his lineswitc to operate.

4. In order to provide a sim ler and more reliable arrangement for signal 'ng the called semi-automatic subscriber than has been used heretofore in connection with rural semiautomatic lines, the connectors having access to these lines have been arranged so that the application of coded ringing current is repeated periodically until the called subscriber responds, instead of the previous practice of sending out the coded ringing current following a prolonged attention ring and then terminating the ringing operation independent of the removal of the receiver at the called substation. The resent arrangement has not been employs heretofore owing to the fact that it necessitates the applicationof a current source to the called line from the exchan so that a current flow will be brou ht a out by the removal of the receiver at t e called substation when a direct-current bridge is placed across the line, there being a condenser in series with each of the ringers. It has been considered heretofore that the uncertain state of repair and the consequent poor insulation of many of the rural lines makes this operation impractical. It has been determined, however, by experimentation that this method of operation is satisfactory as long as the source of direct current is not applied during the ringing period. The ring-cut-ofl relay of the connector used to call a semi-automatic line then does not have to resist the combined flow of alternating current and direct current through a leaky line prior to the removal of the receiver. The common ringing apparatus has accordingly been revised so that the source of direct current for operating the ring-cut-ofi relay responsive to the removal of the receiver at the called substation is applied only durin the silent period. With this provision, t e ring-cutofi relay of the connector ma be adjusted so that it will not operate unti the receiver is removed at the called substation if the line is in good condition and will operate rior to the removal of the receiver only i the line is in such poor condition that conversation over the line is practically impossible.

5. Since the connectors used to complete connections to semi-automatic lines are provided with ring-cut-ofi relays, these connectors may be used to give answering supervision by reversing the current flow over the incoming conductors, thus enabling answering supervision to be given to the calling operators and enabling measured service to be given to lines by means of message re 'sters or call meters, if so desired. 11 a dition, arra ments are provided for again reversing t e current flow when the called subscriber rings of! in case the connection is to another semi-automatic line.

6. When a semi-automatic party-line subscriber desires to call another subscriber on the same line, and the operator causes the selector re ater in use to extend a connection to a ring-back switch which is then set for the proper si alling of the called subscriber on t e ca ing line, the ring-ofi' relay in the selector repeater is disconnected so as to prevent the release of the connection respionsive to the ringing current coming bac from the ring-back switch. In order to bring the release of the connection again under the control of the calling line, the ringing circuit is automatically opened and the ring-01f relay is again connected up by a timing device after an interval of one minute, as by this time the. calling subscriber will have taken note of his code of ringing current if he is within hearing distance of his telephone. 7

7, The sending device employed in the reg ster senders of the system disclosed herein is arranged so that the interval between successive igits is. governed by a grou of counting relays whlch count off a de nite number of impulses from the impulse generator of the sender, instead of depending upon the releasing time of slow-acting relays as in the case of most previous senders.

8. Owing to the fact that the semi-automatic lines have local-battery substantions thereon and are not supplied with talking current from the central exchange, it has not been found practical to use the same toll train for use in completing connections to semi-automatic lines as is used in completing connections to the common-battery automatic lines. This'is largely due to the arrangement in the standard toll train wherein a toll transmission selector, preceding the toll connector, is used to supply talking current to the calledline and to give answering and disconnect supervision to the toll operator. Accordingly, a toll connector has been designed especially for use in completing connections to semi-automatic local-battery lines and has been arranged to give the operator the same type of supervision she receives when using t or as nearly so as is practical.

Description of drawings Other objects and features of the invention are concerned with the provision of suitable circuit arrangements for enabling e standard toll train,-

gu ses the invention; Figs. 2 to 14 show by means of the usual circuit diagrams a suflicient amount of the apparatus involved in the system of Fig. 1 to enable the invention to be understoo and Fig. 15 is a layout drawing showing how the sheets on which Figs. 2 to 14 are drawn should be assembled together in order to be understood best.

Description-of trunking layout, Fig. 1

Referring now particularly to 1, two exchanges, EX-l and EX-2, are shown. The exchange EX-l is a remotely-controlled semi-automatic magneto exchange, the control over the switching apparatus therein being exercised through the medium of the operating trunks" OTl and- OT2 by operators located in the exchange EX-2.

The exchange EX-2 is a combination exchange. It is assumed that there are at present in the neighborhood of two thousand common-battery automatic lines served by the exchange EX-2, of which the lines of substation A7 and A8 are shown; and that there are about one hundred semi-automatic magneto lines, of which the lines of substations A4 A5, and A6 are shown. In the exchange ldX-l, there are assumed to be about 200 lines of which the lines of substations A1, A2, and A3 are shown.

Local calls in exchange EX-Q Referring now particularly to the exchange EX-2, the way in which calls are completed therein will be explained'generally. Assume first that the subscriber at substation A7, 'whose number is 3280, desires to call the subscriber at substation A8,

' whose number is 4450.

Call from automatic substation A7 to automatic substation A8 When the subscriber at substation A7 removes his receiver, the lineswitch LS6 operates in the usual manner responsive to the current flow over the two conductors of his line in series, and selects a regular two-wire first selector FS. This selector, it may be stated, operates as a thousand selector when a call is being made through it to any one of the common-battery lines.

The calling subscriber at substation A7 now operates his calling. device in accorddiallin of the first digit 4, the second selector S2 is prepared .for operation in the usual manner, and it res onds to the dialling of the second di 't 4 y raising its wiper opposite the fourt level of bank contacts and selecting an idle trunk extending to a connector in the fourth hundreds, group of the fourth thousands roup, the local connector LC5, for examp e.

Having been selected responsive to the dialling of the first two digits 4 -and 4 in the desired number, the local connector LC5 responds to the last two digits 5 and 0, by raising its wipers opposite the fifth level of bank contacts and by rotating them overthe bank contacts in the fifth level, until they come to rest on the tenth set of these bank contacts, thus connecting with the line of substation A8. The usual busy test is made, and if the line is found to be idle, ringing current is applied in the usual mannet, and the subscriber at substation A8 is thereby signalled that he is desired in conversation.

When the subscriber at substation A8 responds to the ringing of his bell by removing his receiver (not shown), the local connector L05 reverses the direction of current flow in the trunk line incoming thereto ,for the purpose of operating a message reg-' ister or meter at the calling substation in case the calling substation is so equipped, or for the purpose of giving supervision to an operator in case one is calling, or for similar purposes.

The two subscribers may thereupon carry on their conversation, and whenit is completed they both replace their receivers. As in most standard automatic systems, the two selectors FS and SS2 release responsive to the receiver being replaced at the calling substation A7, but the connector LC5 does not release responsive to the replacement of the receiver at the calling substation in case the called subscriber has not replaced his receiver. The connector LS5 is accordingly not released until the receiver has been replaced at both substations.

Call from automatic substation A8 to automatio substation A7 In case the subscriber at substation A8 desires to call the subscriber at substation A7, whose number is 3280, the removal of the receiver at substation A8 results in the operation of the lineswitch LS5 to seize a first selector, such as the selector FS, following which the connection is set up in the manner described above, except that the calling subscriber in this case dials the digits 3, 2, 8, and 0. The connection may take the path shown through the second selector SS1 and the connector L64.

Selector repeaters multipled with first i selectors In order that the semi-automatic subscribers may be connected with an desired one of the automatic lines, the se ector repeater SR2, which is one of a group provided to handle calls from the semi-automatic lines, has all of its levels with the exception of the ninth and tenth multipled with the corres onding levels of the first selector FS. he se ector repeater SR2 is so arranged that the impulses delivered thereto after it has been set are repeated to the selectors and connectors such as F81 and FS2 and LC4 and LS5 to operate them in the same manner as when the subscriber at substation A7 or the subscriber at substation A8, is calling. Accordingly, the selector repeaters, such as SR2, and the first selector, such as FS, have common access on the second level to the group of connectors represented by the local connector LC3, which have access to the 100- line group of semi-automatic magneto lines.

Call from semi-automatic substation A6 to semi-automatic substation A4 The way in which the subscribcn'at substation A6, whose number is 2751, sets up a connection to the party-line subscriber at substation A4 whose number is 2322, will now be described. When the subscriber at substation A6 desires to make a call, he removes the receiver at his telephone in order to signal the operator, as in regular manual practice. When this occurs, the line switch LS3, actuated by current from the local battery at the calling telephone, responds by extending the calling line to an idle selector repeater, such as SR2. When the selector repeater SR2 is seized, a finder, such as the nder F3, is started to connect a sender, such as the sender SE1, to the selector repeater SR2. Also, the operators finder F4 operates to associate the operators telephone 0T1 with the sender SE1. When this connection is completed, the operator converses with the calling subscriber and ascertains the desired number 2322. Upon doing this, the operator sets up the digits of the desired number on the registering apparatus of the register sender in use, following which the register sender sends out the digits of the number and then initiates the release of the finder F3.

When the first digit 3 is sent out, the selector repeater SR2 operates to raise its wipers (not shown) opposite the second level of bank contacts, and thereupon selects an idle connector, such as the local connector L03. When the connector L03 is seized, it is prepared for operation in the same way as any regular two-wire connector, and it responds to the next two digits 3 and 2 1n nausea the desired number to raise its wipers opposite the third level of bank contacts and to rotate them into enga ent with the second set of bank contacts in the third level. The fourth and last digit 2, the party-selecting digit, is responded to by a party selector which selects the ringing code correspondin to the digit 2, allowing which the se ected code is intermittently transmitted over the called line.

When the subscriber at substation A4 responds to the ringing of his bell by removing his receiver, a direct current momentarily flows over his line and causes the cessation of the ringing operation and the completion of the talking connection. The current flow in the inconnng conductors of the connector LC3 are reversed in the same manner as when a regular automatic subscriber responds to the signalling of his line b a connector such as the connector LC4. he two subscribers may now converse with each other in the usual manner.

Upon the termination of the conversation, the two subscribers replace their receivers, whereupon the connection releases respon sive to the cessation of current flow from the local battery at the calling telephone.

The called subscriber is expected to ring ofi when he hangs u In case he does this before the calling su scriber hangs up, the connector L03 responds by reversing the direction of current flow in its incoming conductors back to normal, causing the selector repeater SR2 to release and open the connection to the connector LC3 and permits its release.

Call from automatic substation A7 to semiautomatic substation A4 In case a connection is desired from an automatic line, such as the line of substation A7, to a semi-automatic line, such as the line of substation A6, the connection may be completed by way of the first selector FS and the connector LC3, and the current flow is reversed back to the calling line by the-connector LC3 when the called subscriber at substation A4 responds, as is-the case when the line at substation A7 is connected to a called automatic line. In case the called semi-automatic subscriber rings off before the calling subscriber hangs up his receiver, the reversal of the direction of current flow in the calling line back to normal, effected by the connector LC3, does not result in the release of the connection, but the connection remains established until the calling subscriber replaces his receiver, whereu on the switches FS and L03 are both re eased.

Call from semi-automatic substation A6 to automatic substation A7 When a call is made from a semi-automscic line, such es the line of subsection A6, to en eulsomuiic line, such as the line of sub section Al, the connection may include the switches SE2, SS1, and LCl. "in this case, the switches S312, and SS1 are released in case the calling subscriber st substation Ad rings 05 While the receiver is still ed as snhsiebion A7, leaving the connector LU -l operated under the conirol of the celled line. Un the other hand, if the suhscriher cl, substation A"? replaces his receiver before the calling subscriber or. subsection Ac rings ed, she selector repeater SE2 is re leased responsive to the reversal of current flow in its heel: bridge heclr lo norrnel, whereupon she svrirches SS1 and LE4 are hoih released,

lineal cells in escheng 525-] In she exchange ELK-l, local calls are com pleled in the iofiovving manner: Assuming chenille subscriber er, substation ill, vvhose niunher is 3581, desires so cell the suhscriher or, su osss'liion A3, Whose nim oer is 4581; the sppliceiion or rbging currens to lire ceiling line lay the usual operation of the hand genereior es suhssslion 2L1 resuli'ss in the opera "sion of the linesvviich LS2 to seize an idle selector repeater such as 331., W hen the re-,

pester SR1 is seine-d, e finder, such as F1, is started and it makes connection with the selector repeater Sill, Also, e control is exercised over the operating trunk GT1 to cause a finder such as to connect e sender to the operating lrunlr Tl, and the operaizors finder 1M connects the operetor s telephone UT lo the sender, V

The operator now converses with ihe celling subscriber at suhsl-eiion Al and ascerieins the desired number 4581. This numher is set up by the operator on the regisier sender in use, whereupon the digits, 5, 8, end 1, of the number are transmitted over the operating trunk GT1 to set the necessary switches in the exchange EX-l after which the finders F1 and F3 used in completing the conirolling connection to the sender are released.

Responsive to the first digit 4, the selector repeater SR1 raises its Wipers opposite the fourth level and rotates them in search of an idle trunk line. Assuming that the trunk line leading to the local connector LC2 in the fourth hundreds group is the first one found to be idle, the connector LCQ is seized and is prepared for operation.

.Eesponsive to the second and third digits 5 and 8, the local connector LE2 raises its wipers opposite the 5th level of bank contacts and rotates them into engagement with the eighth set of contacts in this level. The fourth and last digit 1 conditions the associated apparatus to signal the called line in accordance with the first of the ten codes, the

" first of the ten party-line codes being used 3-687, the completed connection may include;

the line switch LS1, the selecior repeater SR1 (raised lo-the third level), end the loc -cl connector L'Ol (set on the eighth set of contacts in thesixcli level). The ep licen lion of ringing current so the coiled line is in sccordence-with the flour-1th and last digil 1. Al 3 .1, ol'lG sevenni of ice ten codes being uses lo signal the subscriber ec substation A2.

Two opernling trunks @Tl end (3T2 are provided because the ernounl, of irsfic orig insied by two hundred lines is ordinarily more than can be satisfactorily handled over one operating trunk.

Handling reverting calls In the exchange EX-l, it will be noted that the ringeech switch RES-l is secesslble lo the selector repeater SR1 by way of the lllllliil level. l filien e party-line suhscrio er desires to converse with another suhscriloor on the same line, he signals the operator in the usual manner, who esccriains the destination oi the cell and then causes the corn nection to he extendc by the selector repester to e ring-heck switch such as PBS-i. The ring-heels switch is set to send the code of the desired subscriber beclr over the cell ing line. The ceiling subscriber hangs us soon as he finishes conversing with she operator, and he Waits until his hell sounds the called partys code, The ringing circuit is automatically opened when either of the two subscribers removes his receiver.

A similar arrangement is employed in the second exchange, involving ring-heck switches such as liBfi-i Zncrcilange calls (toll Toll connections to end. from the regular common-battery lines of exchange EEK-2 are handled through the toll hoard shown in i; e lower right-hand corner of Fig. 1 hy means of regular slenderd toll-service equipment (not shown). Special toll-service trunk equipment and toll-recordingequipmsnl is provided for handling all toll cells involv mg any semi-automatic lines of either exchange. in case a subscriber desires to con-= verse with a subscriber other than one his ovvn exchange, it is necessary for to get into communication with the toll-re cording operator who directly com letes the toll connection; or passes the in ormation over to the regular toll operator for her use in later completing the connection, in case ill?) the connection cannot be set u while the' calling subscriberwaits on the line.

A subscriber of exchan e EX-l, desiring a toll connection, signals t e operator in the manner described, and asks for long distance. The re ar trafic operator at the telephone OT 0 Fi 1 sets up the digit 0 on the re ister sen er, causing the selector repeater R1 of Fig. 1 to be raised to the tenth level. This extends the connection to an idle toll trunk such as the toll trunk TT. It ma hap n in some installations that one to t will be sufiicient, but in most cases two or more toll trunks such as TT will have to be provided. Connection to the toll trunk TT from the tenth level of the selector repeater SR1 is made by way of the ringing repeater RR which automatically ma es a momentary a plication of ringing current to the toll tr TT upon seizure in order to si al the operator through the medium of t e (grugk cilrcuit TR3. 'lllhe op; erator on s u into t e jac J3 by m g iis of hei c rdgaiiliit (not shown). The operator then completes the toll connection or records the request for such connection, according to circumstances.

In order to complete a toll connection to one ofthe lines of exchange EX-l, the line of substation A3, for example, either the toll operator or the toll-recording operator may plug into the jack J3 or into one of its multiples and complete a connection with the toll trunk TT by way of the trunk circuit TR3. By this operation, the toll selector TS, which is a regular two-wire selector, is prepared for operation in the usual manner. The calling operator then dials the four digits 4, 5, 8, and 1 of the number. The toll selector TS responds by raising its wipers to the fourth level and seizing an idle toll. connector such as TC2, one or more being provided for each hundred-line group, dependin upon conditions. The toll connector T responds tothe second and third digits 5 and 8 by making connection with the line of substation A3, and is conditioned for the roper signalling of the substation by the al digit 1.

The toll connector T02 is arranged to 'give su rvision to the calling operator compara le to that given when the operator is using a standard toll train to call a regular two-wire automatic line.

It will be noted that the toll connector TGl has it banks connected in multiple with the local connector LCl in order to provide for the completion of toll calls to the third hundreds glOltE.

Regarding e handling of toll calls involving the semi-automatic lines of exchange EX-2, it will be noted that the trunk lines leading from the tenth level of the selector repeater SR2 extends to the toll board by way of trunk circuits, such as TRl; and t at the toll connector TC3, similar to the toll connectors T01 and TC2, is accessible b wa of the toll board through the jack 2 an the trunk circuit TRl.

General description of FigaZ-M Referring now to the circuit drawings, Figs. 2 to 14, these drawings will be exlained a little further. As mentioned ereinbefore, the sheets on which these drawings are made should be assembled in the manner indicated in Fig. 15, drawn on the same sheet with Fig. 9. When the drawings are thus assembled, Figs. 2, 3, and 4 show the switching equipment necessa for setting up connections in exchange X-2 from either of the two semi-automatic lines of Fi 2 to the other, or from either of these 'nes to any other semi-automatic line in the same exchange. The line of substation A6, Fig. 2, terminates at the exchange in the lineswitch LS3 which has access to a number of trunk lines, one of which is the trunk line including conductors 221 to' 224, and extending to the selector repeater SR2, Fig. 3. The lineswitch LS4, in which the party line of substation A5 terminates, also has access to the trunk line extending to the switch of Fig. 3, as the bank contacts of all of the lineswitches terminating the semi-automatic lines are multipled together. Fig. 2 shows also the master switch MS which controls the lineswitches such as LS3 and LS4.

The selector repeater SR2 of Fig. 3 has access by way of the second level to local connectors such as the local connector LC3 of Fig. 4, which is accessible by way ofthe trunk line comprising conductors 361-- 363.

-The finder F3, shown in Fig. 5, is one of a group of finders, each individual to a separate register sender, having access to the selector repeaters such as SR2, as explained in connection with Fig. 1. The startin of an idle one of these finders is controlle by the finder-control relays FCR2, which in turn are controlled over the start conductor 350.

The apparatus to the right of the irregular dotted line running up across Fig. 6, together with the apparatus of Figs. 7 and 8, constitutes one register sender (the sender SE-l of Fig. 1), and is individual to the finder F3, Fig. 5. The remaining uipment to, the left of the dotted line in ig. 6 is associated with the operator and iscommon to all of the register senders. This includes the finder F4, which connects the operators telephone T1 to the register sender and finder F3, and the operators digit keys, shown at the extreme left-hand portion of the sheet.

Fig. 11 shows the finders F1 and F2 that termlnate the operating trunks 0T1 and 

